Summary

All thargoids regenerate at a constant rate (0.4% of their health per second), though since stronger variants have more overall hull, it leads to more effective regen. Once a heart is exerted however, they regenerate very rapidly, so the heart needs to be destroyed to actually damage the interceptor.

With immense firepower, this increased regeneration can be overcome, so large groups of pilots can instantly destroy an interceptor, without destroying its hearts. (This is referred to as ‘instagibbing’)